docs: def handle_scd(self, conn, args):
          """No support for smart-card device protocol."""
          reply = {
              (b'GETINFO', b'version'): self.version,
          }.get(args)
          if reply is None:
              raise AgentError(b'ERR 100696144 No such device <SCD>')
          keyring.sendline(conn, b'D ' + reply)